Chuck attachment



v Aug. 7, 1945. y c. P. STEWART 2,381,087

CHUCK ATTACHMENT Filed April 18, 1944 BY W VA'ITRNEY` Patented Aug. 7," 1945 UNITED STATES a PATENT OFFICE v z,3s1,os'z CHUCK ATTACHMENT Charles P. Stewart, Los Angeles, Calif. Application April l18, 1944, Serial No. 531,543 k i s Claims. (Cl. 'f7- 55) This invention relates to an attachment for chucks adapted to hold and rotate drills.

'Ihere are many instances, such as in the course'of airplane construction where a multiplicity of small holes must be drilled through sheet metal parts for the reception of rivets, bolts, or other fastening devices.l Under these circumstances the actual depth of thehole is relatively small, being only the thickness of the sheet metal part. Usually such holes are drilled by means of air drivencr otherwise portable drills and considerable Idiiliculty has heretofore been experienced in connection with drill breakage. The conventional ydrill supplied for this purpose is relatively long as compared with its' Aquired whenever a drill has become dulled or lt accompanying drawing for an illustrative embodiment of the invention, wherein:

Figure 1 is a view in side elevation of the conventional Jacobs chuck illustrating the attach-v ment embodying the presentinvention as hav-` ing been applied thereto;

are applied to the drill during the drilling causing the drills to break.

An object of the present invention is to provide an attachment for chucks such as are employed on air driven or otherwise portable drills which will eiectively brace the shank of the drill so that only the required length of thel drill therein a counterbored-bushing through which the drill may extend. By means of the adjustment the bushing may .be advanced or retracted to leave the desired length of drill projecting therefrom and as the drill shortens due to successive resharpenings the bushing may be retracted so .as .to leave only the desired length -.ofunsupported drill projecting therefrom. By means of the counterbore which is lcapable of receiving the chuck jaws a very compact, sturdy construction is possible.

Another object of the'invention is to provide a chuck attachment having .the above-mentioned characteristics `wherein4 provision is made for protectingthe sheet metal when the drill conipletes the drilling of the hole so that chuckattachment will not scaror otherwise injure sheet metal being drilled.

Another object of theinvention is provide a I the'4 Fig. 2 is a view of the chuck on an enlarged scale the attachment being shown in vvertical section taken substantially on the line 2 2 upon Fig. 1;

Fig. 3 is a top plan view of the attachment and may be regarded as having been taken"sb'- stantially upon the line 3- -3 upon Fig. 2; and

Fig. 4 is a horizontal section taken substantially upon the line 4,-4 upon Fig. 2.

' Referring to the accompanying drawing wherein similar reference characters Idesignate similar parts throughout, I0 indicates the body of a conventional Jacobs chuck on which is rotatable a collar I'I having beveled teeth I 2 by which the collar l'may be rotated relatively to the body I0 by means of a pinion-key, not shown, to open or close the jaws I3 that are designed to be tightened around the drill D. The body I0 may be attached in any suitable manner to the spindle of an air driven or otherwise portablev drill.A Frequently the body I0 has its upper end internally threaded for attachment to the spindle. p Below the teethv I2 the body I0 is usually equipped with three circumferentially spaced apertures or recesses any of which may receive the short-cylindrical shank on the pinion. Such apertures are indicated at I4. y

The attachment embodying the present invention comprises a tubular body I5, the upper end of which is enlarged so as to be telescopically receivable over the lower portion of the body Ill. In this .upper enlarged portion there are two threaded holes I6 and IT arranged opposite two of the holes or recesses I4, thus serving to fasten the body I5 onto the body I 0 of the chuck so that it will rotate with the chuck. Opposite the threaded recess or aperture I4 the enlarged upper portion ofbody I5 is formed with an opening I9 which exposes the-thirdv aperture or recess to permit the insertion or application of the pinion chuck attachment lapplicable to a conventional .Tacobs chuck which utilizes apertures or yre cesses already formed on -the chuck body for attaching the attachment to the chuck and which is so constructed that the attachment does not interfere with normal tightening and loosening operationsv of the chuck which may be rethe drill D extends.

key in the conventional manner to rotate the collar II. The lower portion of the body I5 is internally threaded to receive a bushing 20 having an axial bore 2I therethrough through which This bore is of such a size as to fit somewhat snugly about the shank of the drill D, soV as to support it or brace it vagainst lateral forces thatmay be applied thereto. The

bottom of the bushing may be equipped with a knurled rib 22 by which it can be rotated relaside of the bushing there is a vertical groove 23 into which a set screw 24 may be tightened to hold the bushing in adjusted position. 25 is a leather washer that is slipped onto the drill D and assumes a position against the bottom of the bushing. This washer prevents the lower end of the bushing coming in direct contact with the work which might scar or otherwise damage the work at the time that the drill completes its hole through the work.

As will be noted from an inspection of Fig. 2, the upper end of the bushing is counterbored as indicated at 26 to receive the lower portions of the jaws I3 When the bushing 20 approaches its fully a more retracted position so as to leave substantially the same length of drill projecting therefrom.

As the attachment rotates with the chuck no bearing surface need be provided between the bushing 20 and the sides of the drill. Cuttings will normally be scatteredl by the drill during its rotation and the washer 25 not only serves `to protect the work, but prevents or retards entry of cuttings between the drill and the bushing. Whenever it is desired to replace a drill the pinion key may be applied to the body of the chuck through opening I9 in the conventional manner and the collar II rotated to loosen the jaws I3. A replacing drill may be inserted through the bore 2| in the bushing and the'collar again tightened; If the replacing drill is of a diierent size a differently-sized attachment may have to be applied to the chuck or a differentlysized bushing employed for this purpose. The

attachment can be readilydetached from the chuck by loosening the set screws I 8.

It will be appreciated from the above-described construction that the attachment is extremely compact in form and may be very economically constructed and. applied to the conventional Jacobs chuck without requiring modication or alteration thereof. l

' Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. In combination with a chuck having a body with three circumferentially spaced recesses and a toothed collar on rotation of which the jaws of the chuck may be tightened and loosened. a tubular body'telescopically arranged over the chuck body having two set screws adaptedto enter two of said recesses and having an opening exposing the third recess to permit insertion' of the collar-turning key for the chuck, and means on said body closely encircling a drill clamped by the chuckjaws for bracing the drill against lateral forces. A

2. In combination with a chuck having a bodir with three circumierentially spaced recesses and.

, of the collar-turning key for the chuck, and a bushing threaded into said body for advancement and retraction therein, said bushing iitting about a drill in the 'chuck jaws, and means for holdingv the bushing in adjusted position.

3. In combination with a chuck having a body with three circumferentially spaced recesses and a toothed collar on rotation of which the jaws of the chuck may be tightened and loosened, a tubular body telescopically. arranged over the chuck body having two set screws adapted to enter two of said recesses and having an open' ing exposing'the third recess to permit insertion of the collar-turning key for the chuck, and a bushing threaded into said body for advancement and retraction therein, said bushing iitting about a drill in the chuck jaws, and means for holding the bushing invadjusted position, said bushing being counterbored to receive the chuck jaws as the bushing approaches 4its -fully retracted position.

4. An attachment for chucks comprising a tubular body adapted to be telescopically positioned over the body of a chuck, the upper end of said body being enlarged having two circumferentially spaced set screws receivable in circumferentially spaced recesses in the chuck body and `an opening exposing a third recess in the chuck body, and a bushing threaded into said body having a bore therethrough adapted to closely receive a drill.

5. An attachment for chucks comprising a tubular bodyvadapted to be telescopically positioned over the body oi.' a chuck, the upper end of said body being enlarged having two circumferentially spaced set screws receivable in circumferentially spaced recesses in the chuck body and an opening exposing a' third recess in the chuck body, and a bushing threaded into said body having a bore therethrough adapted to closely receive a drill, and a leather washer adapted to be positioned about the drill against the end of the bushing. v

6. An attachment for chucks comprising a tubular body adapted to be telescopically positioned over the body of a-chuck, the upper end of said body being enlarged having two circumferentially spaced set screws receivable in circumferentially spaced recesses in the chuck body and an opening exposing a third recessvin the closely receive a drill, "said bushing beingcounterbored to receive jaws of the chuck.

CHARLES P. STEWART. 

